Cached := Proc clone.
A Cached object is a procedure which stores a lazy-evaluated
value. The first time the procedure is invoked, the value is computed,
as per a stored procedure. The result is stored, so that later calls
to the procedure can simply return the value. Cached objects are
most commonly created using the memo
global method.
Cached toString := "Cached".
Cached value.Returns the value computed from the stored procedure. If the value has
not been computed yet, this method returns Nil.
Cached done?.Returns True if and only if the stored procedure has been invoked
and the value set.
Cached procedure.This is the stored procedure itself. Its default value is the global
Proc object, but it is frequently overriden in subobjects to a
correct implementation of the stored procedure work. This should not
be an evaluating object and should also not return an evaluating
object as its result. It should also work correctly when passed no
arguments.
Cached call.If the stored value has already been computed (done?), returns the
stored value (value). Otherwise, this method simply returns the
stored value.
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